''Now I want to emphasise my electorate of North Sydney has one of the highest bulk-billing rates in Australia and I have one of the wealthiest electorates in Australia,'' Mr Hockey told ABC radio. ''To me there is something wrong with that.''

In fact, Mr Hockey’s electorate had Sydney’s fifth-lowest bulk-billing rate, 70 per cent, according to 2010-2011 Department of Health data, the most recent available. This is below thenational average.

A spokeswoman for Mr Hockey declined to provide any data to support the Treasurer’s comments, saying only: ''The electorate has a high rate of bulk-billing for affluent areas.''

The government’s expenditure review committee has reportedly approved a $6 co-payment, capped at 12 GP visits, meaning patients would pay a maximum of $72 extra each a year. The Medicare fee push is based on a proposal by former Howard government adviser Terry Barnes, who estimated the fee would save the budget $750 million over four years by reducing unnecessary GP visits.

Health groups have attacked the GP co-payment idea, warning it will hit the poor and sick hardest and place additional pressure on already stretched emergency departments.

''We know that $6 is enough for people to make decisions and defer treatment,'' Australian Medical Association president Steve Hambleton said.

''Yes some discretionary visits will disappear, but some important visits will disappear as well.''